Hello, advice and information needed

Hi, I'm considering whether to buy an xbox or wii (ps3 too expensive) although I'm almost entirely persuaded by the wii, but have a few questions that hopefully someone here can help me with.

Firstly, how much do snes n64 games etc cost to download?? and how many can i store on the wii?? also by any small chance are these playable online?

Secondly are there a decent amount of good games? i have played new super mario brios wii and loved that. How are games like mario galaxy, zelda, goldeneye, resident evil?? and any others i should be aware of.

Firstly, how much do snes n64 games etc cost to download?
They go off "Wii points" these go from 400 to 1200 for some games

When bought via either the Wii Shop Channel or the Nintendo DSi Shop, 1000 Nintendo Points cost US$10 in the United States, €10 in Europe, £7 for Wii points (£9 for DSi points) in the United Kingdom, and ¥1000 in Japan. When bought retail, the original Nintendo Points Cards, which had values of 2000 Nintendo Points, cost US$19.99 in the United States, €24.99 in Europe, £19.99 in the United Kingdom and AU$34.99 in Australia.

How many can i store on the wii?
Quite a few, but you can save them to a SD card. They are locked to the console.
Also by any small chance are these playable online?
Sadly no

Could you tell me though what games you [play online and if there much fun???

Well, there is the CoD(call of duty) series. -CoD 3 and 2 cannot be played online-. You can play COD MWR (modern warfare reflex) COD WAW (world at war) or COD BO. (black ops) out of all of these, I would recommend COD MWR.